1. Field of the Invention
The present invention relates to a whitening cosmetic composition containing a green tea extract and, more particularly, to a whitening cosmetic composition containing a green tea extract that is prepared from green tea leaves by hot water extraction and then liquid culture with Aspergillus oryzae to provide a high inhibitory effect on tyrosinase.
2. Background Art
Human skin color (complexion) is ascribed to various factors, including the activity of melanin-producing melanocytes, the blood vessel distribution, the skin thickness, and the existence of body pigments such as carotenoids, bilirubin, etc. Among these factors, the primary determinant of skin color is a darkening pigment called melanin, which is produced by the actions of different enzymes such as tyrosinase, etc. in the melanocytes. There are three main factors that affect melanin production: genetic factors, physiological factors related to hormone secretions, stress, etc., and environmental factors such as ultraviolet (UV) irradiation. Melanin in humane skin plays an important protective role within the human body against UV light, but overproduction of melanin is known to show up as brown patches and spots on the skin and accelerate skin ageing, even causing skin cancer.
To treat or alleviate skin pigmentation, such as brown spots or patches, and excessive melanin pigmentation caused by UV exposure, cosmetics or medical products have been formulated in combination with ascorbic acid, kojic acid, arbutin, hydroquinone, glutathione, or their derivatives, and tyrosinase-inhibitory substances. However, those substances are restrained in their use due to insufficient whitening effect, skin-safety problems, problems with formulation and safety in cosmetic use, and so forth.